DelicateTreeFrog

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About DelicateTreeFrog

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  1. Thank you for your replies, guys! The idea of using one shader with uniforms is that the individually generated shaders would all just be copies of the same source code, but with the diffuse color, specularity, etc tweaked during load time based on the contents of the corresponding .obj materials. In this situation, "master shader" may be a bad name for it, since it really only contains the necessities that would apply to all objects (instead of being overloaded with features which aren't often used), with the objects tweaking the shader's uniforms for specularity (a value in the range of 0.0 to 1.0), diffuse color, etc based on the particular .obj material in use at the time, versus switching shaders altogether. Would the most benefits come out of doing it this way given these particular circumstances?
  2. Hello! As an exercise for delving into modern OpenGL, I'm creating a simple .obj renderer. I want to support things like varying degrees of specularity, geometry opacity, things like that, on a per-material basis. Different materials can also have different textures. Basic .obj necessities. I've done this in old school OpenGL, but modern OpenGL has its own thing going on, and I'd like to conform as closely to the standards as possible so as to keep the program running correctly, and I'm hoping to avoid picking up bad habits this early on. Reading around on the OpenGL Wiki, one tip in particular really stands out to me on this page: For something like a renderer for .obj files, this sort of thing seems almost ideal, but according to the wiki, it's a bad idea. Interesting to note! So, here's what the plan is so far as far as loading goes: Set up a type for materials so that materials can be created and destroyed. They will contain things like diffuse color, diffuse texture, geometry opacity, and so on, for each material in the .mtl file. Since .obj files are conveniently split up by material, I can load different groups of vertices/normals/UVs and triangles into different blocks of data for different models. When it comes to the rendering, I get a bit lost. I can either: Between drawing triangle groups, call glUseProgram to use a different shader for that particular geometry (so a unique shader just for the material that is shared by this triangle group). or Between drawing triangle groups, call glUniform a few times to adjust different parameters within the "master shader", such as specularity, diffuse color, and geometry opacity. In both cases, I still have to call glBindTexture between drawing triangle groups in order to bind the diffuse texture used by the material, so there doesn't seem to be a way around having the CPU do *something* during the rendering process instead of letting the GPU do everything all at once. The second option here seems less cluttered, however. There are less shaders to keep up with while one "master shader" handles it all. I don't have to duplicate any code or compile multiple shaders. Arguably, I could always have the shader program for each material be embedded in the material itself, and be auto-generated upon loading the material from the .mtl file. But this still leads to constantly calling glUseProgram, much more than is probably necessary in order to properly render the .obj. There seem to be a number of differing opinions on if it's okay to use hundreds of shaders or if it's best to just use tens of shaders. So, ultimately, what is the "right" way to do this? Does using a "master shader" (or a few variants of one) bog down the system compared to using hundreds of shader programs each dedicated to their own corresponding materials? Keeping in mind that the "master shaders" would have to track these additional uniforms and potentially have numerous branches of ifs, it may be possible that the ifs will lead to additional and unnecessary processing. But would that more expensive than constantly calling glUseProgram to switch shaders, or storing the shaders to begin with? With all these angles to consider, it's difficult to come to a conclusion. Both possible methods work, and both seem rather convenient for their own reasons, but which is the most performant? Please help this beginner/dummy understand. Thank you!
  3. SketchUp and Java

    If you plan on using SketchUp, your best option may be to export your SketchUp models to .obj format. That way, you have a lot of options to choose from library-wise, including writing your own importer, since the .obj model format is very straightforward and a great place to start. If you want animated objects that can bend, however, I suggest learning Blender and using an intermediate format that supports skeletal deformation such as .dae, since SketchUp and .obj do not meet these requirements. Blender's learning curve is steeper than SketchUp's, but it's free, doesn't bog down your system like other professional 3D modeling software, and is very rewarding once you get the hang of it. Likewise, parsing .dae files (or whatever other skeletal object format you go with) will be a headache at first if you aren't familiar with the territory, but, like .obj, there should be libraries available that work well enough if you don't want to write your own importer. Best of luck!